1. Field of the Invention
The present invention relates to a grade displaying apparatus, and more particularly, to an apparatus for automatically classifying liquid crystal display devices according to grades and displaying each grade to the outside, if each grade is determined after the liquid crystal display devices are completed.
2. Discussion of the Related Art
A liquid crystal display device is thin, light and portable, and thus has been widely used as an image displaying device.
Such a liquid crystal display device may be provided with a liquid crystal display panel comprising a color filter substrate for displaying an image in colors, a thin film transistor array substrate attached to the color filter substrate, and a liquid crystal layer filling in a cell gap formed between the array substrate and the color filter substrate.
The thin film transistor functions as a switching device for applying or cutting off an electric field to/from the liquid crystal is arranged in a matrix form at the thin film transistor array substrate.
Additionally, in the color filter substrate, sub-color filter layers of red, green and blue for displaying information in colors are formed at every unit pixel.
The thin film transistor array substrate and the color filter substrate are manufactured using different production lines. Then they are formed as one unit cell through attaching and cutting processes.
In addition, a liquid crystal is injected into the liquid crystal display panel manufactured through the above steps to form one unit liquid crystal display panel.
When the liquid crystal display panel is formed through these processes, an auto verification process is performed to examine the driving state of the completed liquid crystal display panel and determine whether it is inferior.
The auto verification process is used to determine whether the liquid crystal display panel is inferior by displaying a predetermined image on the completed liquid crystal display panel. The auto verification process examines whether the driving of colors is good, whether a voltage is properly applied to each unit pixel, whether there is a line defect or a point defect on a screen displaying unit, whether there is a stain on a screen, or the like. On the basis of the inspected results from the auto verification process, an operator determines a grade or rating of the liquid crystal display panel and inputs it to equipment such as a computer.
If the grade of the liquid crystal display panel corresponds to a predetermined standard, the operator inputs the grade of the liquid crystal display panel to a computer, or the like. The liquid crystal display panel is transferred to a predetermined storing place by a robot controlled by a host.
A plurality of cartridges may be classified into several grades and arranged at the storing place of the liquid crystal display panels. A robot arm stores the liquid crystal display panel which have been graded to the cartridge based on its determined grade.
However, determination of the grade varies according to a client's request. Namely, what one client regards as inferior may be accepted by another client. In addition, according to uses of the image displaying device using the liquid crystal display panel, an acceptable range of inferiority may be different. Accordingly, the grade is not fixed but changeable on demand.
Moreover, since the cartridge in which the liquid crystal display panel whose grade has been determined is stored has no means to check the grade, a product having a different grade may be shipped.
And, to check the grade, each cartridge may be marked manually. However, when a standard for grade and the cartridge in which the liquid crystal display panel having a predetermined grade is stored are changed, the corresponding cartridge should be manually re-marked.